This disclosure related to a system and method for implementing hybrid schemes of mode decision by a Base Station in a Wireless Metropolitan Area Network (WMAN) described in the IEEE 802.16 specification.
In a WMAN communications network, a base station (BS) may communicate with a mobile station (MS) on a communication channel. Various factors such as the existence of ambient interference around the MS or BS, movement of the MS, system level information of the BS, and/or other factors may degrade or otherwise alter the condition of the communication channel. As such, various channel information may be used to indicate the channel condition. For example, there exists a variety of channel information such as, for example, channel correlation (Corr), Rank, a Physical Carrier to Interference plus Noise Ratio (PCINR), a Received Signal Strength Indicator (RSSI), a Burst Error Rate (BuER) based on an ACK/NACK ratio that indicates a proportion of successful data transmissions to unsuccessful transmission (thereby indicating channel stability), PCINR Standard Deviation that may indicate Doppler and fading effects that result from movement of the MS, system loads, and/or other indicators.
In order to respond to changes to the communication channel, the BS may use different mode configurations. Mode configurations may include, among other things, a Multiple-Input-Multiple-Output (MIMO) mode selection, a Modulation Coding Scheme (MCS) level selection, and/or other mode configurations.
In existing systems, the BS generates a mode configuration that the BS has determined to be suitable. The BS-derived mode configuration may be used in these existing systems irrespective of the particular conditions of the communication channel and irrespective of information available to the MS that may be unavailable to the BS. In other existing system, the MS may generate a recommended mode configuration that the MS has determined to be suitable. In these existing systems, the MS-derived mode configuration may be used again irrespective of the particular conditions of the communication channel and irrespective of information available to the BS that may be unavailable to the MS.
Thus, by using either an exclusive BS-centric or exclusive MS-centric approach to mode decision, existing systems may not adequately make an appropriate mode decision because in some instances the BS may have more information applicable to the mode decision than the MS while in other instances the MS may have more information applicable to the mode decision than the BS.
These and other drawbacks exist.